Photosensitive coating containing dyes



i atenteci Mar. 13. 195i *Henry B. 'Staehle, ltochester, N. Y.,assigiio'r' t6 =Ea'stinan:Koda.k.-C0ml a y;1R0. hStL;N..Yn.-ficorporation of New Jersey He man e iaINo. gene's App a ion Mays. 194?.

,sel ims. (ores- 5s) :1 "This invention relates tothe preparation ofsensitive; photographic materials and part'icu'larfly to sensitivematerials containing dyes-for the formation.0f @o lt d ,ima

Iii-my U.--s. application, Serial No. 558,346, filed October 12, 19%,.1havedescribedthe preparation of photographic reversal images in acoating :ofvbichromated hydrophilic colloid .such as gelatin or glue,containing an aqueous-dispersion eta water-insoluble, soft syntheticresin capable of drying to a continuous film when the dispersioniscoatedpn glass. I preferto use as the,soft, synthetic, resin an aqueousdispersion of an acrylate resin .suchas polymethylacrylate or polylacryiate, a polystyrenedispersion, a polyvinyl acetate dispersion orneoprene latex. A dispersion of plasticized cellulose nitrate in watermay also be employed. The mixture may also contain a wetting ordispersing agent such as a sodium alkyl sulfate or a polyethylene glycoland a plasticizing agent such as glycerol or ethylene glycol. In myprior application, Serial No. 558,346, I disclosed the incorporation ofwhite pigments such as titanium oxide or colored pigments such as carbonblack, cobalt blue or yellow ochre in the mixture. While titanium oxidemay be incorporated in the sensitive material to form a satisfactorycoating, the replacement of titanium oxide with colored pigments or dyesdoes not ordinarily result in a satisfactory product. Many of thecommonly used inorganic pigments react with the ammonium bichromate anddestroy the sensitivity of the material.

It is an object of the present invention to provide a novel method forproducing colored images in a bichromated hydrophi-lic colloidcontaining an aqueous dispersion of a soft, synthetic resin. A furtherobject is to provide colored images which are transparent to light.Other objects will appear from the following description of myinvention.

These objects are accomplished by incorporating in the sensitivematerial made according to the process of my prior application, Ser. No.558,346, in place of the titanium oxide or other pigment, anywater-insoluble dye which is commonly used for dyeing cellulose acetatefabrics. Azo dyes having the following formula are frequently used ascellulose acetate dyes and are suitable for use according to myinvention:

R. is an arylene nucleus of the benzene series, X is hydroxyl, amino orsubstituted amino such as dihydroxydialkylamino or R'.; may be a pyrazolone nucleusattached in the i-position to the Jazegrdup."Antlira'quinonedyesmay also'be used.

-Dyes"which'mayb used according to my invention are described" inRe'ddelienand 'Matzdorf U; S.'=-Patent 15673 301,.June.l2,.l928, E1115and Croft UJ-S. Patent 1,'600.277, September 21, 1926,

These dyes are water insoluble.

According to my invention a colloidal dispersion of a'water-insolubIebut resin-solubledye is in'eor'peratea me bichromatedhydrophiliccolloid mixture containifiga' dispersion bfa water irisoh t;synthetic resin: The "tinctorialpower speiisionds -c'o'n'iparativel'y'ilow so that the presence" ofthe dyf'e'veri' though .it'is stronglyblue-absorbing has comparatively little actinic light absorption in itscolloidal state. After exposing and processing the sensitive layer, thefull color of the dye is brought out by exposing the image to a solventfor the dye in the vapor phase.

My invention will be further illustrated by reference to the followingexample.

Seven grams of 4-nitrobenzeneazo-2-methyl- 4-di- 3-hydroxyethylani1ine(cake) are dissolved in 75 cc. of warm acetone. This solution is addedto 175 cc. of 15% gelatin solution to which 5 cc. of a sodium alkylsulfate dispersing agent has been added. To produce a smooth dispersionof the dye in the gelatin solution, the mixture may be run through acolloid mill.

A sensitive mixture is prepared by mixing 30 cc. of a 15% gelatinsolution with 18 cc. of polymethyl acrylate of polyethyl acrylate resindispersion in water. To this mixture is added 20 cc. of the dye gelatinmixture. To this there is added 1 /2 cc. of 20% ammonium bichromatesolution and 5 drops of ammonium hydroxide. The sensitive mixture isthen applied by brushing or spraying on a surface such as metal,lacquered surfaces, plastics such as white polyvinyl acetate, etc., andexposed under an image. The layer is processed by washing with water,the exposed portions washing away leaving those portions of the imagewhich were not exposed to light.

Although the final image is strongly colored, the full brilliance andpurity ofthe dye must be brought out by a subsequent treatment. One

method of accomplishing this is to spray a lacquer, the solvent of whichis a solvent for the dye, over the image. This, however, causes a slightbleeding of the dye with consequent destruction of minute detail.Another method which is preferable is to subject the final image to thevapor of a solvent of the dye such as ,3 acetone vapor. This immediatelybrings the dye to its full brilliance without any perceptible bleedingof the dye, unless there is a condensation of liquid acetone on theimage surface. The image can also be immersed in an emulsion ofchloroform and water to increase the brilliance.

Multi-colored images may be prepared by repeating the spraying, exposingand processing cycle with as many different colored materials as desiredsince the presence of one image does not interfere with the applicationof a subsequent coating.

I claim:

1. The method of making a colored photographic image which comprisescoating a support with a bichromated hydrophilic colloid, an aqueousdispersion of a synthetic resin of the group consisting of polymethylacrylate and polyethyl acrylate and mixtures thereof and awaterinsoluble azo dye of the general formula:

where R. is an aryl radical of the benzene series, B. is an aryleneradical of the benzene series, X is selected from the class consistingof hydroxyl and amino, drying said coating, exposing said coating to animage, and washing away the exposed parts of said coating to leave saidcoating containing said azo dye in the unexposed portions.

2. The method of making a colored photographic image which comprisescoating a support with bichromated gelatin containing an aqueousdispersion of a synthetic resin of the group consisting of polymethylacrylate and polyethyl acrylate and mixtures thereof containing 4-nitrobenzeneazo-2-methyl-4-di-B-hydroxyethyl aniline, drying saidcoating, exposing said coating to an image, and washing away the exposedparts of said coating to leave said coating containing said azo dye inthe unexposed portions.

3. The method of making a'colored photographic image which comprisescoating on a support with a bichromated hydrophilic colloid, an aqueousdispersion of at least one synthetic resin of the group consisting ofpolymethyl acrylate, polyethyl acrylate, styrene, vinyl acetate andneoprene resins, and a water-insoluble azo dye of the general formula:

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number 7 Name Date 1,981,102 Hagedorn Nov. 20,1934 2,043,905 Seymour June 9, 1935 2,184,310 Meigs Dec. 26, 1939

1. THE METHOD OF MAKING A COLORED PHOTOGRAPHIC IMAGE WHICH COMPRISESCOATING A SUPPORT WITH A BICHROMATED HYDROPHILLIC COLLOID, AN AQUEOUSDISPERSION OF A SYNTHETIC RESIN OF THE GROUP CONSISTING OF POLYMETHYLACRYLATE AND POLYETHYL ACRYLATE AND MIXTURES THEREOF AND AWATERINSOLUBLE AZO DYE OF THE GENERAL FORMULA: